THE STUDY OF CANCER 7 



took definite shape on the basis of a scheme of research sub- 

 mitted to the Executive Committee by myself in October, 1902, 

 and diligent search was instituted into the occurrence of cancer 

 not only in all races of mankind, civilised and aboriginal, but 

 also throughout the animal kingdom. A farm was secured for 

 observations on the larger domesticated animals suffering 

 naturally from cancer, and every opportunity was utilised of 

 testing the possibility of transferring the disease and studying 

 it under experimental conditions. The scheme of experimental 

 research, thus embarked on, received an unexpected justifica- 

 tion and a great impetus by the publication of Jensen's accurate 

 and fundamental observations on the inoculation of a tumour 

 of a mouse in 1903, and contemporaneously of those of Borrel. 

 Since then valuable work has also been done by Apolant, 

 Haaland, Loeb, Michaelis, Henke, and, above all, by Ehrlich. 



Jensen's great service consists in the fact that he did not 

 restrict himself to demonstrating the reproduction at the site 

 of inoculation of the features of the original growth. He also 

 proved, 1 by carefully following the processes at the site of 

 inoculation step by step, that the new formation was due to 

 the continued growth of the cells peculiar to the tumour, parts 

 of which he had introduced. Jensen's work has been energeti- 

 cally followed up in all civilised countries, and in the first 

 instance in the laboratory of the Imperial Cancer Research 

 Fund. 



The investigations of Murray and myself on an adeno- 

 carcinoma mammae and Jensen's own tumour confirmed his 

 observations, and, by extending them to a large number of other 

 malignant new growths in mice, established the experimental 

 study of cancer on a secure foundation ; so that, after some 

 preliminary controversy, it is now universally agreed, infection 

 plays no part in the process of experimental transference. On 

 the contrary, transference to fresh mice merely affords the cancer 

 cell an opportunity for continuing to proliferate in fresh soil. 

 With Murray I made an exhaustive study of the processes at 

 the site of the inoculation of cancerous tissue in the case of 



1 This demonstration is sometimes erroneously attributed to L. Loeb, who 

 obtained tumours on inoculating sarcoma in rats in 1901-3. Loeb's original 

 description of the processes at the site of inoculation does not bear this interpreta- 

 tion. He also admitted the possibility of the tissues surrounding the grafts 

 acquiring sarcomatous properties. 



